AS-Interface motor starter with brake control
The Siemens SIRIUS 3RK4320-3GQ51-0BA3 is a direct motor starter MCU designed for AS-Interface networks — it handles starting and overload protection for a single motor load while communicating status and control over the AS-i bus. Includes a motor brake output controlled at 400 V AC — useful for conveyors or hoists that need a holding brake released when the motor starts.
Panel fit and mounting constraints
Dimensions are 205 mm deep by 245 mm wide by 215 mm tall — this is a compact unit for a combined starter + AS-Interface node, but the 245 mm width means it needs a full DIN-rail bay; check your enclosure's usable rail length before committing. IP54 protection — splash-resistant, not washdown-rated; fine for dry factory-floor cabinets but not for food-processing wash zones or outdoor installation without a secondary enclosure.
AS-Interface integration and supply requirements
Communicates via AS-Interface protocol (no PROFIBUS or PROFINET onboard — this is a dedicated AS-i node), with 2 digital inputs for local sensors or limit switches wired directly to the starter. Control supply is 20.4–26.4 V DC — standard AS-Interface power, so it draws from the AS-i yellow cable or a dedicated 24 V DC supply; the main motor circuit runs on 340–440 V AC at 50 or 60 Hz. Rated for 80 operating cycles per hour minimum — fine for intermittent conveyor starts but not for high-cycle indexing applications that need a higher switching frequency.
RoHS compliance dated to 05/01/2012 per the substance prohibitance entry — the part meets the EU RoHS directive for the current exemption period.